One patient has been studied with intraperitoneal administration of Tc-99m B72.3 and 3 patients with intravenous administration. No localization in tumor has been observed for the patients receiving intravenous administration of B72.3, and is probably related to the short half life of Tc-99m and the prolonged time necessary for optimal antibody localization in tumor. A direct comparison of Tc-99m and I-125 B72.3 suggest that there is some instability of the Tc-99m labeled on the methallotionein. The study is still open for accrual.